Compressor and oxygen condensing device

ABSTRACT

Provided is a compressor, and an oxygen concentrator, that achieve low noise by which the noise does not leak directly to the exterior upon generation of compressed air through suction of raw air, and that allow reducing power consumption of a driving motor. 
     A compressor has a case section; a driving motor provided in the case section and having an output shaft; head sections operated by the rotation of the output shaft of the driving motor and that suck and compress raw air to generate thereby compressed air; a raw air intake section that is provided at the output shaft and that takes in the raw air into the head sections as a result of the rotation of the output shaft and that supplies the raw air towards the head sections; and a pressure regulation section that regulates the pressure within the case section upon suction of the raw air and upon discharge of the generated compressed air.

TECHNICAL FIELD

The present invention relates to a compressor and to an oxygen concentrator having the compressor. More particularly, the present invention relates to a compressor and an oxygen concentrator for medical uses capable of supplying oxygen by compressing intake raw air and feeding the compressed air to an adsorbent.

BACKGROUND ART

In oxygen concentrators, oxygen is obtained in accordance with a pressure swing adsorption method in which oxygen in raw air is caused to pass through a zeolite or the like, as an adsorbent, that selectively adsorbs nitrogen.

In oxygen concentrators of this type, the intake raw air is compressed by a compressor, as compression means, to generate compressed air, and the compressed air is fed to an adsorbent-packed adsorption cylinder, where nitrogen is adsorbed onto the adsorbent, to yield oxygen as a result. The generated oxygen is stored in a tank and is brought to a state that enables supply of a predetermined flow rate of oxygen from the tank, via a reducing valve of a flow rate setting unit. Thereby, a patient can inhale the oxygen using an implement such as a nasal cannula.

For instance, patients having impaired lung function and being under home oxygen therapy can breathe oxygen safely even when in bed, and can sleep hence soundly, if such an oxygen concentrator is installed at a site where AC power source (commercial AC power source) can be used.

Preferably, the oxygen concentrator makes very little noise, in particular, when used in bed by patients under home oxygen therapy. Preferably, the noise of the oxygen concentrator does not exceed, for instance, the noise level of indoor air conditioning.

Oxygen concentrators used for long-term oxygen therapy, which is effective as a therapy for patients having a respiratory disease such as chronic bronchitis, are ordinarily not transportable, and are not configured to be carried to such sites as the patient may move to.

Thus, when the patient is forced to go out, he/she must inhale concentrated oxygen out of an oxygen cylinder, being a container of a predetermined capacity filled with oxygen and placed on a cart that is pushed by the patient. Such oxygen and cylinders must be filled at dedicated facilities.

Thus, transportable and/or mobile oxygen concentrators have been proposed wherein the transportable or mobile oxygen concentrator is provided with a battery-drivable compressor that comprises compression means for generating compressed air by taking raw air in, and with pressure reduction means for generating reduced-pressure air (Patent document 1).

Patent document 1: Japanese Patent Application Laid-open No. 2002-45424

SUMMARY OF INVENTION Technical Problem

The above-described conventional oxygen concentrator has an air inlet for sucking in raw air, in a piston crankcase. The piston is operated through rotation of the motor output shaft of the compressor, as a result of which raw air in the form of external air is directly sucked into the piston, via the air inlet, to generate compressed air thereby. Upon operation of the compressor, however, noise was known to leak directly out of the piston crankcase, via the air inlet. Therefore, it would be desirable to generate compressed air by causing raw air to be reliably sucked into a piston, with little noise, while reliably preventing direct leaks of noise to the exterior via the air inlet.

Power consumption incurred by motor driving must be reduced, in particular, in transportable or mobile oxygen concentrators in which compressed air is generated through motor driving.

Therefore, it is an object of the present invention to provide a compressor, and an oxygen concentrator, that boast low noise in that noise does not leak directly to the exterior upon generation of compressed air through suction of raw air, and that allow reducing power consumption of a driving motor.

Solution to Problem

The compressor of the present invention is a compressor that generates compressed air through compression of raw air, wherein the compressor has a case section and a driving motor that is provided in the case section and that has an output shaft; a head section operated by the rotation of the output shaft of the driving motor and that sucks and compresses the raw air to generate thereby the compressed air; a raw air intake section that is provided at the output shaft and that takes the raw air into the case section, as a result of the rotation of the output shaft, and supplies the raw air to the head section; and a pressure regulation section that regulates the pressure within the case section upon suction of the raw air and upon discharge of the generated compressed air.

By virtue of the above configuration, noise is reduced in the compressor of the present invention since noise does not leak directly to the exterior upon generation of compressed air through suction of raw air, and pressure within the case section can be regulated upon suction of the raw air and upon discharge of the generated compressed air. This allows reducing the power consumption of the driving motor.

In the compressor of the present invention, the pressure regulation section has a first pressure regulating valve that can open and close a first opening, and a second pressure regulating valve that can open and close a second opening, in order to regulate the pressure within the case section upon suction of the raw air and upon discharge of the generated compressed air.

The above configuration allows reducing power consumption in the driving motor through adjustment of the pressure within the case section, by way of a simple structure, upon suction of the raw air and upon discharge of the generated compressed air.

In the compressor of the present invention, the raw air intake section of the output shaft has: a screw that guides the raw air in an axial direction of the output shaft, at an end section of the output shaft; and a tubular-type bearing member that takes the raw air into the case as a result of the rotation of the screw.

Such a configuration allows raw air to be quietly taken into the case section while preventing, as much as possible, direct leaking to the exterior of noise from the compressor.

In the compressor of the present invention, the driving motor is provided at a face section on a first side of the case section; and the raw air intake section of the output shaft is provided at a face section on a second side of the case section, the second side being on the opposite side to the first side.

By virtue of such a configuration, the driving motor and the raw air intake section of the output shaft can be respectively disposed on the first side face section of the case section, and on the opposite second side face section. This affords a smaller and lighter compressor.

In the compressor of the present invention, a hood member for covering the raw air intake section of the output shaft is provided at the case section.

In such a configuration, the hood member can function as a noise-preventing member for preventing noise upon intake of raw air by the raw air intake section of the output shaft, as well as noise of the driving motor itself.

An oxygen concentrator of the present invention is provided with a compressor that generates compressed air through compression of raw air, and an adsorption member that holds an adsorbent that adsorbs nitrogen from the compressed air, wherein the compressor has a case section and a driving motor that is provided in the case section and that has an output shaft; a head section operated by the rotation of the output shaft of the driving motor and that sucks and compresses the raw air to generate thereby the compressed air; a raw air intake section that is provided at the output shaft and that takes the raw air to be supplied to the head section, as a result of the rotation of the output shaft; and a pressure regulation section that regulates the pressure within the case section upon suction of the raw air and upon discharge of the generated compressed air.

In the oxygen concentrator provided with the compressor of the present invention, by virtue of the above configuration, noise does not leak directly to the exterior upon generation of compressed air through suction of raw air, and pressure within the case section can be regulated upon suction of the raw air and upon discharge of the generated compressed air. This allows reducing the power consumption of the driving motor.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention succeeds in providing a compressor, and an oxygen concentrator, that boast low noise in that noise does not leak directly to the exterior upon generation of compressed air through suction of raw air, and that allow reducing power consumption of a driving motor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a preferred embodiment of an oxygen concentrator provided with a compressor of the present invention;

FIG. 2 is a perspective-view diagram of a compressor viewed from the front;

FIG. 3 is a perspective-view diagram of the compressor illustrated in FIG. 2 viewed from direction U;

FIG. 4 is a perspective-view diagram of the compressor illustrated in FIG. 2 viewed from direction G;

FIG. 5 is a perspective-view diagram illustrating an internal structure of the compressor of FIG. 2, having part thereof removed, as viewed in an oblique direction from the top;

FIG. 6 is a perspective-view diagram of an exploded first head section of the compressor of FIG. 2;

FIG. 7 is a cross-sectional diagram illustrating the compressor illustrated in FIG. 3, along line P-P in direction V;

FIG. 8 is an exploded perspective-view diagram illustrating a hood member; and

FIG. 9 is a diagram illustrating an outline shape of a compressor, denoted by a two-dot chain line, and a raw air introduction channel and a discharge channel, denoted by arrows.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention are explained in detail below with reference to accompanying drawings.

FIG. 1 is a block diagram illustrating a preferred embodiment of an oxygen concentrator provided with a compressor of the present invention.

In a preferred embodiment, an oxygen concentrator 1 illustrated in FIG. 1 is a portable (also referred to as transportable or mobile) oxygen concentrator. The oxygen generation principle resorted to in the oxygen concentrator 1 illustrated in FIG. 1 is, for instance, a compressed-air pressure swing adsorption method (PSA: positive pressure swing adsorption) by compressed air.

In a positive pressure swing adsorption method relying on compressed air alone, nitrogen is adsorbed through feeding of compressed air alone through the interior of an adsorption barrel. A positive pressure swing adsorption method is advantageous in that the compressor is smaller and lighter than in a vacuum-pressure swing adsorption method (VPSA) that utilizes both compressed air and reduced-pressure air.

The double lines illustrated in FIG. 1 denote ducts that constitute flow passages of raw air, oxygen and nitrogen gas. The thin solid line denotes wiring for power source supply or for electric signals. The broken line denotes a main chassis 2 of the oxygen concentrator 1 illustrated in FIG. 1. The main chassis 2 is a hermetic container that seals the elements that are disposed within the main chassis 2. For instance, the main chassis 2 is an injection molding resin article formed out of a thermoplastic resin having impact resistance.

The main chassis 2 illustrated in FIG. 1 has an air intake port 2 c for introduction of raw air, in the form of external air, and an outlet port 2 b for discharge. A filter 3 for removing impurities such as dirt and dust in the air is disposed at the air intake port 2 c. Upon operation of the compressor 10, raw air is introduced into the compressor 10 via the filter 3 of the air intake port 2 c and via an inner duct 4, in direction F.

The raw air is introduced to the compressor 10 via the duct 4 and is compressed to yield compressed air. Heat is generated upon compression of the raw air. Accordingly, the compressed air discharged out of the compressor 10 is cooled through rotation of a blower fan 5. Cooling of the compressed air allows suppressing rises in the temperature of a zeolite, as an adsorbent, the performance whereof drops at high temperatures. Sufficient performance of the adsorbent for generating oxygen through adsorption of nitrogen can be ensured as a result, so that oxygen can be concentrated to about 90% or above.

A first adsorption barrel 108 a and a second adsorption barrel 108 b, as an example of an adsorption member, are disposed in parallel in a vertical direction. Respective three-way switching valves 109 a, 109 b, as switching valves, are connected to the first adsorption barrel 108 a and the second adsorption barrel 108 b. From among these switching valves, one end section of the three-way switching valve 109 a is connected to a duct 6. The three-way switching valve 109 a and the three-way switching valve 109 b are connected to each other. Further, one end section of the three-way switching valve 109 b is connected to a duct 7.

The duct 7 and the duct 6 are connected to each other. The duct 7 is connected to the duct 6 in order to perform a purification process of causing unwanted gas to desorb from the interior of the first adsorption barrel 108 a and the second adsorption barrel 108 b. The three-way switching valves 109 a and 109 b are respectively connected to the first adsorption barrel 108 a and the second adsorption barrel 108 b. The compressed air generated in the compressor 10 is alternately supplied to the first adsorption barrel 108 a and the second adsorption barrel 108 b via the duct 6 and the three-way switching valves 109 a, 109 b.

A zeolite, as a catalytic adsorbent, is stored in the first adsorption barrel 108 a and the second adsorption barrel 108 b. The zeolite is, for instance, a zeolite X in which the Si₂O₃/Al₂O₃ ratio ranges from 2.0 to 3.0. The adsorption amount per unit weight is increased through the use of a zeolite in which at least 88% or more of Al₂O₃ tetrahedral units are bonded to lithium cations. In particular, the zeolite has preferably a granulometric value smaller than 1 mm, and at least 88% or more of tetrahedral units are fused with lithium cations. The amount of raw air that is used as required for oxygen generation can be reduced through the use of a zeolite, as compared with cases in which other adsorbents are used. As a result, the compressor 10 for generating compressed air can be made smaller and less noisy.

As illustrated in FIG. 1, a uniform pressure valve 107, comprising a check valve, a throttle valve and an on-off valve, is connected to the outlets of the first adsorption barrel 108 a and the second adsorption barrel 108 b. A merging duct 8 is connected to the downstream side of the uniform pressure valve 107. A product tank 111 is connected to the duct 8. The product tank 111 is a container for storing oxygen of a concentration of about 90% or higher that is separated at the first adsorption barrel 108 a and the second adsorption barrel 108 b.

As illustrated in FIG. 1, a pressure regulator 112 is connected to the downstream side of the product tank 111. The pressure regulator 112 is a regulator for automatically adjusting the pressure of oxygen at a predetermined level on the outlet side of the product tank 111. An oxygen concentration sensor 114 of zirconia type or ultrasonic type is connected to the downstream side of the pressure regulator 112. The oxygen concentration sensor 114 detects oxygen concentration intermittently (every 10 to 30 minutes) or continuously.

As illustrated in FIG. 1, a proportional-opening valve 115 is connected to the oxygen concentration sensor 114. On the basis of a signal from a flow rate control unit 202, prompted by a command by a central control unit 200, the proportional-opening valve 115 opens and closes in response to a setting button operation of an oxygen flow rate setting button 308. An oxygen flow rate sensor 116 is connected to the proportional-opening valve 115. A demand valve 117 is connected to the oxygen flow rate sensor 116 via a reduced-pressure air circuit board for oxygen conserve control breath synchronization control). The demand valve 117 is connected to the oxygen outlet 9 of the oxygen concentrator 1 via a sterile filter 119.

An adapter 313 of a nasal cannula 314 is removably connected to the oxygen outlet 9. The adapter 313 is connected to the nasal cannula 314 via a tube 315. With the nasal cannula 314, the patient can inhale, for instance, oxygen concentrated to about 90% or above, at a maximum flow rate of 1 L/minute. Performing oxygen conserve control (breath synchronization control) through control of the demand valve 117 elicits conceivably the same effect as supplying, to the patient, substantially a maximum 3 L/minute of oxygen concentrated to 90% or above as a result of oxygen conserve control (breath synchronization control), given that the IE ratio (ratio between inspiration time (seconds)/expiration time (seconds)) is ordinarily 1:2.

A power source system illustrated in FIG. 1 is explained next.

A connector 430 of an AC (commercial AC) power source illustrated in FIG. 1 is connected to an AC adapter 419 of switching regulator type. The AC adapter 419 rectifies AC voltage from a commercial AC power source to a predetermined DC voltage. A built-in battery 228 is provided, for instance, at the bottom of the main chassis 2. An external battery 227 is removably provided via a connector 431. A power source control circuit 226 is electrically connected to connectors 430, 431.

The built-in battery 228 and the external battery 227 are repeatedly rechargeable secondary batteries. The built-in battery 228 can be charged by receiving power supply from the power source control circuit 226. The external battery 227 can also be charged by receiving power supply from the power source control circuit 226. Ordinarily, however, the external battery 227 is repeatedly charged using a battery charger that is provided separately.

As a result, control of the power source control circuit 226 by the central control unit 200 of FIG. 1 makes it possible to automatically switch to one supply state from among a total of three system power supply states, namely a first power supply state in which power supply is received from the AC adapter 419, a second power supply state in which power supply is received from the built-in battery 228, and a third power supply state in which power supply is received from the external battery 227. The built-in battery 228 and the external battery 227 may be lithium ion or lithium hydride ion secondary batteries that can be fully charged during recharge thanks to their small memory effect upon charging. The built-in battery 228 and the external battery 227 may also be conventional nickel cadmium batteries or nickel hydride batteries. For emergencies, the external battery 227 may be configured, for instance, in the form of a box of C-size batteries that are procurable anywhere.

The central control unit 200 of FIG. 1 is electrically connected to a motor control unit 201 and a fan motor control unit 203. The central control unit 200 stores a program that switches between optimal operation modes in accordance with the amount of oxygen to be generated. In response to commands from the central control unit 200, the motor control unit 201 and the fan motor control unit 203 automatically drive the compressor 1 and the blower fan 5 at high speed, when a substantial amount of oxygen is to be generated, and cause the compressor 1 and the blower fan 5 to be rotationally driven at a lower speed when little oxygen is to be generated.

The central control unit 200 has built therein a ROM (read-only memory) that stores a predetermined operation program. An external storage device 210, a volatile memory, a temporary storage device 208 and a circuit comprising a real-time clock are also electrically connected to the central control unit 200. The central control unit 200 can access stored content through connection to a communication circuit 444 or the like via an external connector 433.

A control circuit (not shown) that performs control, as well as flow rate control unit 202 and the oxygen concentration sensor 114, are electrically connected to the central control unit 200 in such a manner that unwanted gas in the first adsorption barrel 108 a and the second adsorption barrel 108 b is desorbed through on-off control of the three-way switching valves 109 a, 109 b and the uniform pressure valve 107 illustrated in FIG. 1. The flow rate control unit 202 performs driving control of the proportional-opening valve 115, the flow rate sensor 116 and the demand valve 117. Also, a oxygen flow rate setting button 308, a display unit 128 and a power source switch 306 are electrically connected to the central control unit 200 illustrated in FIG. 1.

The oxygen flow rate setting button 308, for instance, allows setting an oxygen flow rate, of oxygen concentrated to about 90% or above, each time the button is operated in 0.01 L (liter) stages from 0.25 L per minute to a maximum of 1 L per minute. Substantially 2 L/minute of oxygen at a concentration of 90% or higher is supplied to the patient through oxygen conserve control (breath synchronization control).

Accordingly, there is preferably provided an oxygen conserve mode (a synchronization mode) selection switch (not shown) that can be operated by the patient. The display unit 128 that is used may be for instance a display device such as a liquid crystal display. On the display unit 128 there can be displayed, for instance, display items such as an operation indicator, an oxygen indicator, a synchronization mode, a charge indicator, remaining battery power, cumulative time, oxygen flow rate and so forth. For instance, a display “oxygen conserve mode”(“synchronization mode”) may be lighted up in green during the time at which oxygen conserve control breath synchronization control) is active.

An explanation follows next, with reference to FIG. 2 to FIG. 6, on an example of a preferred structure of the compressor 10 illustrated in FIG. 1.

FIG. 2 is a perspective-view diagram of the compressor 10 viewed from the front. FIG. 3 is a perspective-view diagram of the compressor 10 illustrated in FIG. 2 viewed from direction U. FIG. 4 is a perspective-view diagram of the compressor 10 illustrated in FIG. 2 viewed from direction G. FIG. 5 is a perspective-view diagram illustrating an internal structure of the compressor 10 of FIG. 2, having part thereof removed, as viewed in an oblique direction from the top. FIG. 6 is a perspective-view diagram illustrating an exploded first head section of the compressor 10 of FIG. 2.

The compressor 10 illustrated in FIG. 2 and FIG. 3 causes compressed air to be fed to the interior of the first adsorption barrel 108 a and the second adsorption barrel 108 b illustrated in FIG. 1, according to a positive pressure swing adsorption method (PSA) in which, as described above, only compressed air is generated, and nitrogen in the compressed air is adsorbed by the adsorbent in the first adsorption barrel 108 a and the second adsorption barrel 108 b.

The compressor 10 in FIG. 2 and FIG. 3 is a two-head compressor having a driving motor 11, a first head section 21, a second head section 22 and a case section 23. The compressor is small and lightweight, having a total weight of about 300 g to 900 g. The driving motor 11 is, for instance, a 1 L-class electric motor, but may be, for instance, a single-phase AC induction motor, or a single-phase 4-pole AC synchronous motor.

The first head section 21, the second head section 22 and the case section 23 illustrated in FIG. 2 are for instance made up of aluminum, which is a lightweight metal material, in order to achieve a lighter compressor. However, the foregoing sections can be made up of non-metal material, which is engineering plastic.

The first head section 21 illustrated in FIG. 2 is provided at a first end section (top end section) 23A of the case section 23. The second head section 22 is provided at a second end section (bottom end section) 23B of the case section 23. The first head section 21 and the second head section 22 are reciprocating-driving pump heads that are driven by one output shaft 15 of the driving motor 11. The first head section 21 and the second head section 22 are formed to a substantially vertical symmetrical shape with respect to a rotation center axis CL of the output shaft 15.

The revolutions of the output shaft 15 can be kept constant even upon fluctuation of power source voltage, and a piston of the first head section 21 and a piston of the second head section 22 can be reciprocally driven in direction V in a stable manner, if, for instance a synchronous motor is used as the driving motor 11 illustrated in FIG. 2. The driving motor 11, which is a synchronous motor, can rotate at synchronous revolutions, and hence power consumption can be reduced vis-à-vis that of an induction motor.

The first head section 21 and the second head section 22 illustrated in FIG. 1 allow stably supplying compressed air to the first adsorption barrel 108 a and the second adsorption barrel 108 b. The first adsorption barrel 108 a and the second adsorption barrel 108 b allow stably supplying oxygen, concentrated to 90% or above, at the set oxygen flow rate.

The structure of the case section 23 of the compressor 10 will be explained first with reference to FIG. 2 to FIG. 5.

As illustrated in FIG. 2 and FIG. 3, the case section 23, also called a crankcase, is disposed along direction V. Direction V is perpendicular to the rotation center axis CL.

As illustrated in FIG. 2 and FIG. 3, the case section 23 has a main body 24, a first end section 23A and the second end section 23B. The first end section 23A is a portion at which the first head section 21 is attached, and the second end section 23B is a portion at which the second head section 22 is attached.

As illustrated in FIG. 2, the thickness W of the case section 23 is set to be fairly smaller than the width W1 of the first end section 23A and the second end section 23B. As illustrated in FIG. 3, another transversal width W2 of the case section 23 is set to be slightly smaller than another transversal width W3 of the first end section 23A and the second end section 23B. The width W of the case section 23 illustrated in FIG. 2 is set to be fairly smaller than the other transversal width W2 of the case section 23 illustrated in FIG. 3. As a result, the daze section 23 can be made smaller and thinner than the first head section 21 and the second head section 22.

As illustrated in FIG. 2 and FIG. 3, a driving motor 11 is replaceably fixed, by way of a plurality of bolts 11M, to the first side section 31 of the case section 23. As illustrated in FIG. 4, a circular opening 33 is formed at the second side section 32 of the case section 23. The output shaft 15 of the driving motor 11 protrudes through the opening 33, in direction T, along the center of the opening 33, i.e. along the rotation center axis CL.

As indicated by the broken lines in FIG. 3 and FIG. 4, the case section 23 has a first communicating passage 41 and a second communicating passage 42. The first communicating passage 41 and the second communicating passage 42 are formed parallelly to direction V. The first communicating passage 41 is formed at a first side section 23R of the case section 23. The first communicating passage 41 is provided for the purpose of supplying raw air to the first head section 21 and the second head section 22.

The second communicating passage 42 illustrated in FIG. 3 and FIG. 4 is formed at a second side section 23T of the case section 23. The second communicating passage 42 is provided for the purpose of discharging such compressed air as results from compression of raw air at the first head section 21 and the second head section 22, out of the case section 23 via a compressed air discharge port 37. Another opening 38 is closed off by a cap 38P, as illustrated in FIG. 5.

FIG. 5 is explained next. FIG. 5 illustrates the internal structure of part of the compressor 10.

The first head section 21 has a head cover 51 and a first piston 61 at the top. The head cover 51 is fixed by a plurality of screws 51N, with equal force, against the first end section 23A of the case section 23. A connecting rod 61C is attached to the first piston 61. The connecting rod 61C is attached to the output shaft 15 by way of a bearing member.

As illustrated in FIG. 5, the head cover 51 and so forth is fixed by the plurality of screws 51N in such a manner that an equal fastening force is applied to the first end section 23A. This allows preventing leaks of air out of the first head section 21. Moreover, a plurality of recesses 51S for heat dissipation is formed in the head cover 51, as illustrated in FIG. 5. This allows enhancing the effect of heat dissipation during generation of compressed air. That is, heat is generated upon generation of compressed air through compression of raw air when the first piston 61 in the first head section 21 moves linearly along direction V, from the bottom dead center to the top dead center. This generated heat can be dissipated to the exterior, with good efficiency, by providing the recesses 51S for heat dissipation, whereby the heat-dissipation surface area is increased.

Similarly, the second head section 22 illustrated in FIG. 5 has a head cover 52 and a second piston 62 at the bottom. The bottom head cover 52 has the same shape as that of the top head cover 51. The bottom head cover 52 is fixed by a plurality of screws 52N, with equal force, against the second end section 23B of the case section 23. A connecting rod 62C is attached to the second piston 62. The connecting rod 62C is attached to the output shaft 15 by way of a bearing member. In the example of the figures the head cover 51 of the first head section 21 and the head cover 52 of the second head section 22 have a diamond shape.

As illustrated in FIG. 5, the head cover 52 and so forth is fixed by the plurality of screws 52N in such a manner that an equal fastening force is applied to the second end section 23B. This allows preventing leaks of air out of the second head section 22. A plurality of recesses (not shown) for heat dissipation are formed at the head cover 52 as well. This allows enhancing the effect of heat dissipation during generation of compressed air. That is, heat is generated upon generation of compressed air through compression of raw air when the second piston 62 in the second head section 22 moves linearly along direction V, from the bottom dead center to the top dead center. This generated heat can be dissipated to the exterior, with good efficiency, by providing the recesses for heat dissipation, whereby the heat-dissipation surface area is increased.

A structure example of the first head section 21 is explained next with reference to FIG. 6.

FIG. 6 is an exploded perspective-view diagram illustrating the first head section 21. The first head section 21 and the second head section 22 have the same stack structure, but in a reversed up-and-down relationship with respect to each other. The structure of the first head section 21 will be explained thus as a representative instance.

FIG. 6 illustrates a head cover 51 of the first head section 21, upper and lower gaskets 191, 192, an upper member 193, a reed valve member 194 and a lower member 195. These members make up a head assembly. The head cover 51 can be evenly fixed to the first end section 23A of the case section 23, yet more reliably, by way of the plurality of bolts 51N, in a state where the gaskets 191, 192, the upper member 193, the reed valve member 194 and the lower member 195 are sandwiched in the sequence illustrated in the figure. The gaskets 191, 192 are provided for the purpose of preventing leaks of raw air to the exterior during compression. The gasket 191 has an opening 199 and the gasket 192 has a circular opening 199B. The reed valve member 194 has two reed valves 194A, 194B. The upper member 193 has openings 193A, 193B, and the lower member 195 has openings 195A, 195B.

As illustrated in FIG. 6, raw air 70 denoted by a solid line arrow is taken in as a result of the continuous rotation of a raw air intake section 90, for feeding raw air, of the output shaft 15. The raw air 70 passes through the first communicating passage 41, through a hole 192H of the gasket 192, a hole 195H of the lower member 195, a hole 194H of the reed valve member 194, a hole 193H of the upper member 193, and an opening 199 of the gasket 191. Further, the raw air 70 passes through an opening 193A of the upper member 193, the reed valve 194A of the reed valve member 194, the opening 195A of the lower member 195 and the opening 199B of the gasket 192, to be supplied into the first piston 61.

The raw air 70 becomes compressed through displacement of the first piston 61 from the bottom dead center to the top dead center, whereupon compressed air 71 is generated. The compressed air 71 denoted by the broken line arrow passes through the opening 199B of the gasket 192, the opening 195B of the lower member 195, the reed valve 194B of the reed valve member 194, the opening 193B of the upper member 193 and the opening 199 of the gasket 191, and passes further through a hole 193 L of the upper member 193, a hole 194 L of the reed valve member 194, a hole 195 L of the lower member 195, and hole 192 L of the gasket 192, and via the second communicating passage 42, so that the compressed air 71 can be discharged out of the case section 23 via the discharge port 37.

The channels of the raw air 70 and the compressed air 71 are identical in the second head section 22.

FIG. 7 is explained next. FIG. 7 is a cross-sectional diagram illustrating the cross-sectional structure of the compressor 10 illustrated in FIG. 3, along line P-P in direction V. The figure, however, depicts not the cross section of the driving motor 11 but the outer shape thereof.

In FIG. 7, the first head section 21 and the second head section 22 have a substantially vertical symmetrical structure with respect to the rotation center axis CL. The first piston 61 of the first head section 21 and the second piston 62 of the second head section 22 are horizontally-opposed pistons that reciprocate in opposite directions along direction V.

In the example of FIG. 7, the second head section 22 performs a suction process whereby raw air is sucked into the second cylinder 62S at the same time that the first head section 21 performs a suction process whereby raw air is sucked into the first cylinder 61S. The second head section 22 performs a compression process of generating compressed air in the second cylinder 62S, through compression of the sucked air, at the same time that the first head section 21 performs a compression process of generating compressed air in the first cylinder 61S through compression of the sucked air. That is, the second piston 62 is positioned at the bottom dead center in the second cylinder 62S at the time when the first piston 61 is positioned at the bottom dead center in the first cylinder 61S. The second piston 62 is positioned at the top dead center in the second cylinder 62S at the time when the first piston 61 is positioned at the top dead center in the first cylinder 61S.

Therefore, the first piston 61 and the second piston 62 reciprocate synchronically over an identical stroke length of about 1 mm to 10 mm, in mutually opposite directions. The amount of compressed raw air is small if the stroke length is shorter than 1 mm, while a stroke length longer than 10 mm results in a longer compressor 10.

Thus, the raw air in the cylinders 61S, 62S is compressed when the first piston 61 and the second piston 62 are positioned at the top dead center, as in the example illustrated in FIG. 7. Conversely, the raw air is in a suctioned state within the cylinders 61S, 62S when the first piston 61 and the second piston 62 are positioned at the bottom dead center. The inner diameter of the cylinder 61S and the inner diameter of the cylinder 62S are identical, ranging from about 20 mm to 60 mm. The amount of compressed raw air is small if the inner diameter of the cylinder 61S and the inner diameter of the cylinder 62S are smaller than 20 mm. An inner diameter of the cylinder 61S and an inner diameter of the cylinder 62S greater than 20 mm makes it difficult to achieve a small and lightweight compressor 10.

An explanation follows next, with reference to FIG. 7, FIG. 5 and FIG. 3, on the structure of the driving motor 11, and on the output shaft 15 of the driving motor 11.

As illustrated in FIG. 3, the driving motor 11 is fixed to the case section 23, on the side of the first side face section 31, by way of bolts 11M. As illustrated in FIG. 7, the driving motor 11 is a substantially cylindrical motor formed to a thin profile along the rotation center axis CL. Preferably, the driving motor 11 is housed within a space 11S between the first head section 21 and the second head section 22. That is, the driving motor 11 is disposed to be accommodated within the space 11S in such a manner that the driving motor 11 does not protrude beyond the first head section 21 and the second head section 22 in the direction of the rotation center axis CL. In other words, the driving motor 11 is preferably accommodated within a region formed by the outline portion of the first head section 21 and by the outline portion of the second head section 22, at the first side face section 31 of the case section 23. As a result, the driving motor 11 is accommodated in such a way so as not to protrude beyond the outline portion of the compressor 10. This contributes to achieving a smaller, lighter and thinner compressor 10.

As illustrated in FIG. 7, the output shaft 15 passes through a bearing section 61N of the connecting rod 61C, and bearing section 62N of the connecting rod 62C, and protrudes beyond the opening 33, along the rotation center axis CL, on the side of the second side face section 32 of the case section 23. The raw air intake section 90 for intake of raw air is formed at the protruding end section of the output shaft 15.

The end section of the output shaft 15 has a screw 90S that, through continuous rotation about the rotation center axis CL, causes raw air to be taken into the case section 23 along the direction of arrow M. That is, a spiral groove is formed at the end section of the output shaft 15, in such a manner that the spiral groove wraps itself around the outer periphery of the end section. The raw air intake section 90 has the screw 90S and a tubular-type bearing member 91D. The screw 90S is formed to have a groove depth ranging from about 1 mm to 10 mm, and a pitch ranging from about 3 mm to 20 mm. A groove depth smaller than 1 mm results in less raw air taken in, whereas a groove depth greater than 10 mm makes for a weaker screw 90S. A pitch longer than 20 mm entails a longer screw 90S, and makes it thus difficult to achieve a small compressor 10.

As illustrated in FIG. 7, an output shaft holding member 91 is fixed to the second side face section 32 of the case section 23. The output shaft holding member 91 is fixed so as to plug the opening 33 of the case section 23. A tubular-type bearing member 91D is fixed to the output shaft holding member 91. The screw 90S of the raw air intake section 90 of the output shaft 15 is inserted into the bearing member 91D. The screw 90S of the raw air intake section 90 of the output shaft 15 is rotatably supported in the tubular-type bearing member 91D.

As a result, upon reciprocation of the first piston 61 and the second piston 62 through continuous rotation of the output shaft 15 of the driving motor 11, the raw air intake section 90 leads raw air along the interior of the spiral groove, and allows raw air to be taken into the case section 23 in the direction of arrow M. Therefore, no separate suction device for raw air need be provided in order to cause raw air to be taken into the case section 23. This affords a smaller, lighter and thinner compressor that has a simpler structure.

Moreover, a screw shape is formed at the end section of the output shaft 15 with a view to cause raw air to be smoothly taken into the case section 23, in the direction of arrow M, as the raw air is spirally guided along the axial direction of the output shaft 15, at the inner peripheral face of the tubular-type bearing member 91D, through rotation of the screw 90S of the raw air intake section 90. Noise is reduced as a result, in that raw air can be quietly taken into the case section 23 while preventing noise from leaking from the compressor 10 directly to the exterior. Through continuous rotation of the output shaft 15, the screw 90S of the raw air intake section 90 of the output shaft 15 allows raw air to be reliably taken into the case section 23 along the direction of arrow M, at the inner peripheral face of the tubular-type bearing member 91D.

As illustrated in FIG. 7, the output shaft holding member 91 is provided with a pressure regulation section 250 for regulating the pressure in the case section 23 upon suction of raw air and upon discharge of the generated compressed air. The pressure regulation section 250 is explained next.

The pressure regulation section 250 has a first opening 99H and a second opening 99G, and a suction-side pressure regulating valve 98H and discharge-side pressure regulating valve 98G. The first opening 99H and the second opening 99G are formed at the output shaft holding member 91. The suction-side pressure regulating valve 98H is disposed in the first opening 99H. The discharge-side pressure regulating valve 98G is disposed in the second opening 99G. Both the suction-side pressure regulating valve 98H and the discharge-side pressure regulating valve 98G are flapper valves in the form of thin, elastically deformable plate-like members.

As illustrated in FIG. 7, the suction-side pressure regulating valve 98H is disposed on the side of an inner face 91N of the output shaft holding member 91. That is, the suction-side pressure regulating valve 98H is disposed inside the case section (crankcase) 23 on a side facing the connecting rods 61C, 62C.

By contrast, the discharge-side pressure regulating valve 98G is disposed on the side of the side of an outer face 91M of the output shaft holding member 91. That is, the discharge-side pressure regulating valve 98G is disposed on the side of the outer face 91M of the output shaft holding member 91, such that the discharge-side pressure regulating valve 98G faces a below-described hood member 92.

The first opening 99H, the second opening 99G, the suction-side pressure regulating valve 98H and the discharge-side pressure regulating valve 98G are provided for regulating the pressure in the case section 23.

Preferably, the raw air intake section 90 of the output shaft 15 is accommodated within a space 11P between the first head section 21 and the second head section 22. The raw air intake section 90 of the output shaft 15 is disposed to be accommodated in the space 11P in such a way so as not to protrude beyond the first head section 21 and the second head section 22, in the direction of the rotation center axis CL. That is, the raw air intake section 90 of the output shaft 15 is preferably accommodated within a region formed by the outline portion of the first head section 21 and the outline portion of the second head section 22, at the second side face section 32 of the case section 23.

The compressor of the present embodiment, thus, is provided on the side of the first end section in the case section 23, and comprises the first head section 21 having a size that allows the first piston 61 to be accommodated therein, and a second head section 22, provided on the side of the second end section in the case section 23, and having a size that allows the second piston to be accommodated in the second head section 22.

As illustrated in FIG. 7, the driving motor 11, as well as the raw air intake section 90 that is driven by the driving motor, are disposed to be accommodated between the first head section 21 and the second head section 22, inward of imaginary extension lines G1, G1 on the outer edge of the head sections 21, 22.

More specifically, the driving motor 11 is disposed on a first side face section being one side of the connecting rods 61C, 62C that drive the above-described first and second pistons, at regions inward of the imaginary extension lines G1, G1 of the outer edges of the respective head sections 21, 22, while the output shaft 15 and the raw air intake section 90 having a hood member 92 are disposed on the second side face section being the other side of the connecting rods 61C, 62C.

As a result, the raw air intake section 90 of the driving motor 11 can be accommodated without protruding beyond the outline of the compressor 10. This contributes to achieving a smaller and thinner compressor 10.

Also, the driving motor and the raw air intake section of the output shaft can be respectively disposed on the first side face section of the case section, and on the opposite second side face section. This affords a smaller and lighter compressor.

The hood member 92 will be explained next based with reference to FIG. 8 and FIG. 7.

FIG. 8 is an exploded perspective-view diagram illustrating the hood member 92. As illustrated in FIG. 7, the hood member 92 is disposed in the space 11P between the first head section 21 and the second head section 22, such that the hood member 92 is attachably and removably fixed to the case section 23, on the side of the second side face section 23P, preferably by way of a mechanical interlocking structure or a screwed structure. In a mechanical interlocking structure, the hood member 92 can be detached from and fitted to the case section 23 with a one-touch operation.

As illustrated in FIG. 7, the hood member 92 covers the raw air intake section 90 of the output shaft 15. The hood member 92 and the filter 95 are disposed coaxially, about the rotation center axis CL, with respect to the raw air intake section 90 of the output shaft 15.

As illustrated in FIG. 8, the hood member 92 comprises a circular hood case 93, a ring-like cover member 94, and a ring-like filter 95. The hood case 93 and the cover member 94 are made, for instance, of plastic or a lightweight metal such as aluminum. The hood case 93 has a large-diameter section 93B and a small-diameter section 93C. The small-diameter section 93C is formed protruding into the large-diameter section 93B in an axial direction E. The large-diameter section 93B has formed thereon a ring-like rib portion 93D that protrudes in the axial direction E. The axial direction E in FIG. 8 is coaxial with the rotation center axis CL illustrated in FIG. 7. The ring-like rib portion 93D and the small-diameter section 93C form a receiving space 93S that receives, and covers off, the raw air intake section 90 of the output shaft 15 as illustrated in FIG. 7.

The ring-like short tubular cover member 94 is fixed to the hood case 93. The ring-like cover member 94 and the hood case 93 may be formed separately or as a single body. A plurality of raw air intake openings 96 is formed, at identical angular intervals, on a side face of the ring-like cover member 94. In the example of FIG. 8 there are formed four raw air intake openings 96 every 90 degrees, but the openings are not limited thereto, and there may be formed one, two, three or five or more raw air intake openings 96. The ring-like cover member 94 and the rib portion 93D are formed coaxially with the center axis E.

The ring-like filter 95 illustrated in FIG. 8 and FIG. 7 is replaceably fitted into the cover member 94, for the purpose of removing impurities such as dust or dirt contained in the raw air that is introduced into the case section 23. So long as the filter 95 can remove impurities, the filter 95 is not particularly limited, and may be a porous material, a nonwoven material or the like.

The hood member 92 having the above structure is accommodated in the space 11P between the first head section 21 and the second head section 22. That is, the hood member 92 is disposed to be accommodated in the space 11P in such a way so as not to protrude beyond the first head section 21 and the second head section 22 in the direction of the rotation center axis CL. As a result, the hood member 92 is accommodated without protruding beyond the outline portion of the compressor 10. This contributes to achieving a smaller and thinner compressor 10.

An explanation follows next, with reference to FIG. 9, on a raw air introduction channel 59 and on a discharge channel 79 of compressed air after compression of raw air, in the first head section 21 and the second head section 22 of the compressor 10.

In FIG. 9 the contour shape of the compressor 10 is denoted by a two-dot chain line, the raw air introduction channel 59 of the compressor 10 is denoted by a solid line and the compressed air discharge channel 79 is denoted by a broken line.

The raw air introduction channel 59 denoted by a solid line in FIG. 5 has the plurality of raw air intake openings 96, the raw air intake section 90 of the output shaft 15, and the first communicating passage 41 that communicates with the raw air intake section 90. The plurality of raw air intake openings 96 is connected to the filter 3 of the air intake port 2 c via the duct 4. The first communicating passage 41 communicates with the interior of the first cylinder 61S, at the top, and the interior of the second cylinder 62S, at the bottom. As a result, the raw air 70 can be supplied into the top first cylinder 61S and the bottom second cylinder 62S via the raw air introduction channel 59 denoted by the solid lines.

The compressed air discharge channel 79 of the raw air after compression has the second communicating passage 42 and the discharge port 37, and is connected to the first adsorption barrel 108 a and the second adsorption barrel 108 b via the duct 6. As a result, the compressed air 80 generated in the top first cylinder 61S and the bottom second cylinder 62S can be supplied to the first adsorption barrel 108 a and the second adsorption barrel 108 b via the second communicating passage 42 and the duct 6.

An operation example of the oxygen concentrator 1 having the compressor 10 as described above is explained next. The central control unit 200 of FIG. 1 issues a command to the motor control unit 201, the motor control unit 201 starts up the driving motor 11 of the compressor 10, and the output shaft 15 of the driving motor 11 illustrated in FIG. 7 and FIG. 9 rotates continuously about the rotation center axis CL. As a result, the first piston 61 of the first head section 21 and the second piston 62 of the second head section 22 illustrated in FIG. 7 reciprocate stably in opposite directions.

In FIG. 7, the second piston 62 is positioned at the bottom dead center in the second cylinder 62S at the same time as when the first piston 61 is positioned at the bottom dead center in the first cylinder 61S. The second piston 62 is positioned at the top dead center in the cylinder 62S at the same time as when the first piston 61 is positioned at the top dead center in the cylinder 61S. As illustrated in FIG. 7, the raw air in the cylinder 61S and the second cylinder 62S are compressed when the first piston 61 and the second piston 62 are at positioned at the top dead center, as in the example illustrated in FIG. 7.

Conversely, the raw air is in a suctioned state within the first cylinder 61S and the second cylinder 62S when the first piston 61 and the second piston 62 are positioned at the bottom dead center.

That is, the air suction process is performed simultaneously at the second piston 62 and the first piston 61 of the first head section 21; thereafter, a compression process is performed in which compressed air is simultaneously compressed and discharged. The above air suction process and compression process are performed repeatedly.

Upon operation of the first head section 21 and the second head section 22 of the compressor 10, the raw air 70 can be sucked into the top first cylinder 61S and the bottom second cylinder 62S via the plurality of raw air intake openings 96 of the raw air introduction channel 59 denoted by the solid line, and via the first communicating passage 41, as illustrated in FIG. 9.

Upon suction of the raw air 70, impurities such as dirt and dust in the raw air can be removed by the filter 3 illustrated in FIG. 9, and also by the separate filter 95 illustrated in FIG. 7. Before impurities accumulate in the filter 95, the latter can be easily cleaned or replaced by removing the hood member 92. This contributes to an easier maintenance of the filter 95.

The screw 90S of the raw air intake section 90 of the output shaft 15 illustrated in FIG. 9 rotates continuously about the rotation center axis CL, as a result of which the raw air is guided between the spiral groove of the screw 90S and the tubular-type bearing member 91D, to be taken thereby into the first communicating passage 41 of the case section 23. Therefore, no separate suction device for raw air need be provided in order to cause raw air to be taken into the case section 23. This makes for a smaller compressor having a simpler structure.

The raw air intake section 90 is shaped in the form of a screw for taking raw air into case section 23. Therefore, the raw air intake section 90 allows raw air to be quietly taken into the case section 23 while preventing noise from leaking from the compressor 10 directly to the exterior.

The hood member 92 covers the raw air intake section 90 of the output shaft 15. As a result, the hood member 92 allows preventing noise from leaking out directly, from the interior of the case section, upon generation of compressed air through suction of raw air as a result of the operation of the pistons through rotation of the output shaft of the driving motor of the compressor. Compressed air can be generated thereby, reliably and with low noise, through suction of raw air towards the pistons.

The hood member 92 can function as a noise leak preventing member that prevents leaking, to the exterior, of noise during intake of raw air, as well as of noise from the driving motor 11 itself. Therefore, the raw air intake section 90 allows raw air to be quietly taken into the case section 23 while preventing noise from leaking from the compressor 10 directly to the exterior.

In FIG. 9, the compressed air 80 generated in the top first cylinder 61S and the bottom second cylinder 62S can be supplied to the first adsorption barrel 108 a and the second adsorption barrel 108 b via the second communicating passage 42, the discharge port 37 and the duct 6.

The first opening 99H, the second opening 99G, the suction-side pressure regulating valve 98H and the discharge-side pressure regulating valve 98G function in order to adjust the pressure in the case section 23 upon generation of compressed air in the compressor 10 through suction and compression of raw air.

That is, the first piston 61 and the second piston 62 move closer to each other in direction V1 during suction of raw air into the first piston 61 and the second piston 62 accompanying the continuous rotation of the raw air intake section 90 of the output shaft 15. As a result, the internal pressure in the case section 23 rises, and the suction-side pressure regulating valve 98H is pushed, whereby the first opening 99H is closed and the discharge-side pressure regulating valve 98G opens the second opening 99G. The pressure in the case section 23 is adjusted as a result in that the pressure can escape out of the case section 23 via the second opening 99G.

The first piston 61 and the second piston 62 move away from each other in direction V2 to discharge (exhaust) the generated compressed air out of the case section 23, from the first piston 61 and the second piston 62. The internal pressure in the case section 23 drops thereby, and, as a result, the suction-side pressure regulating valve 98H opens the first opening 99H and the discharge-side pressure regulating valve 98G closes the second opening 99G. The pressure in the case section 23 is adjusted as a result in that the pressure in the case section 23 is increased on account of the air flowing in via the first opening 98H.

Thus, the pressure in the case section (crankcase) 23 can be kept substantially constant both upon suction of raw air and upon discharge of compressed air. This allows maintaining a constant driving force during reciprocation of the first piston 61 and the second piston 62. Therefore, the first piston 61 and the second piston 62 can reciprocate smoothly without being affected by pressure changes in the case section 23. This results in smaller driving torque fluctuations of the driving motor 11 during reciprocation of the first piston 61 and the second piston 62, which in turn allows reducing power consumption in the driving motor 11.

Power consumption can be reduced in the first power supply state of driving with power supplied by the AC adapter 419, the second power supply state of driving with power supplied by the built-in battery 228 and the third power supply state of driving with power supplied by the external battery 227. In particular, battery power consumption can be reduced in the second power supply state and the third power supply state that rely on batteries. The oxygen concentrator 1 can be used as a result over longer periods of time.

Heat is released upon generation of compressed air through compression of raw air in the compressor 10 of FIG. 1. Accordingly, the compressor 10 is cooled by the blower fan 5 illustrated in FIG. 1. Accordingly, compressed air passes through the duct 6, the three-way switching valves 109 a, 109 b, and through the adsorbent in the first adsorption barrel 108 a and the second adsorption barrel 108 b, in which nitrogen is adsorbed and oxygen is separated as a result. Oxygen at a concentration of about 90% or higher thus separated can be stored in the product tank 111.

The oxygen concentration sensor 114 of FIG. 1 detects the oxygen concentration in the product tank 111. The proportional-opening valve 115 opens and closes in response to the oxygen flow rate setting button 308. The oxygen is supplied to the nasal cannula 314 via the sterile filter 119 and the oxygen outlet 7 of the oxygen concentrator 1. As a result, the patient can inhale, for instance, oxygen concentrated to about 90% or more, at a maximum flow rate of 1 L/minute, via the nasal cannula 314.

Through the use of the compressor 10, the above-described embodiment of the present invention, allows reducing the noise of the compressor 10 upon generation of compressed air through suction of raw air, and allows reducing the size and weight of the compressor 10 and the oxygen concentrator 1.

In a positive pressure swing adsorption method (PSA) by compressed air alone, only compressed air is fed into the adsorption barrels, where nitrogen is adsorbed. This is advantageous in that the compressor can be smaller and have a simpler structure as compared with vacuum-pressure swing adsorption methods (VPSA) that employ both compressed air and reduced-pressure air.

A synchronous motor is preferably used as the driving motor 11, since in that case the revolutions of the output shaft 15 can be kept constant, and the first head section 21 and the second head section 22 can be driven at stable revolutions, even if the power source voltage fluctuates.

In particular, it becomes possible to continuously supply up to 1 L/minute of oxygen concentrated to 90% or above in a small and streamlined transportable oxygen concentrator having reduced power consumption. If an oxygen conserve function (a breath synchronization function)is operative, it becomes possible to supply up to substantially 3 L/minute of oxygen concentrated to 90% or above.

The present invention is not limited to the above embodiment, and can accommodate various improvements and modifications, and allows for variations without departing from the scope of the claims.

The position of the outer face of the driving motor 11 in FIG. 7 may be identical, in the direction of the rotation center axis CL, to that of the outline portions of the first head section 21 and the second head section 22. Alternatively, the position of the outer face of the driving motor 11 may be lower than that of the outline portion of the first head section 21 and the second head section 22.

The oxygen concentrator is not limited to the portable oxygen concentrator illustrated in the figures, and may be, for instance, a stationary oxygen concentrator. The driving motor of the compressor 10 illustrated in the figures is a synchronous motor, for instance of 1 L class (capable of continuously supplying 1 L/minute of oxygen concentrated to a concentration of 90% or higher). The driving motor that is used is not limited thereto, and may be a motor having a capacity greater than 1 L class, for instance 3 L class (capable of continuously supplying 3 L/minute of oxygen concentrated to a concentration of 90% or higher), or 5 L class (capable of continuously supplying 5 L/minute of oxygen concentrated to a concentration of 90% or higher). Various types of motor, for instance a single-phase AC induction motor, may be used as the driving motor.

The first head section 21 and the second head section 22 are disposed in a horizontally-opposed configuration in which the respective pistons reciprocate in opposite directions, but the first head section 21 and the second head section 22 are not limited thereto, and the two pistons may be disposed in a V configuration.

EXPLANATION OF REFERENCE NUMERALS

1 oxygen concentrator, 2 main chassis, 2 c air intake port, 3 filter, 4 duct, 6 duct, 10 compressor, 11 driving motor, 15 output shaft, 21 first head section, 22 second head section, 23 case section, 23A first end section (top end section) of case section, 23B second end section (bottom end section) case section, 59 raw air introduction channel, 70 raw air, 71 compressed air, 79 compressed air discharge channel, 90 raw air intake section of output shaft, 90S screw, 91D tubular-type bearing member, 92 hood member, 93 hood case, 94 cover member, 95 filter, 98H suction-side pressure regulating valve, 98G discharge-side pressure regulating valve, 99H first opening, 99G second opening, 108 a first adsorption barrel (adsorption member), 108 b second adsorption barrel (adsorption member), 250 pressure regulation section 

1. A compressor that generates compressed air by compression of raw air, wherein the compressor has a case section and a driving motor that is provided in the case section and that has an output shaft, the compressor further having: a head section operated by rotation of the output shaft of the driving motor and that sucks and compresses the raw air to generate thereby the compressed air; a raw air intake section that is provided at the output shaft and that takes the raw air into the head section, as a result of the rotation of the output shaft, and supplies the raw air to the head section; and a pressure regulation section that regulates the pressure within the case section upon suction of the raw air and upon discharge of the generated compressed air.
 2. The compressor according to claim 1, wherein the pressure regulation section has a first pressure regulating valve that can open and close a first opening, and a second pressure regulating valve that can open and close a second opening, in order to regulate the pressure within the case section upon suction of the raw air and upon discharge of the generated compressed air.
 3. The compressor according to claim 1, wherein the raw air intake section of the output shaft has: a screw that guides the raw air in an axial direction of the output shaft, at an end section of the output shaft; and a tubular-type bearing member that takes the raw air into the case as a result of the rotation of the screw.
 4. The compressor according to claim 2, wherein the raw air intake section of the output shaft has: a screw that guides the raw air in an axial direction of the output shaft, at an end section of the output shaft; and a tubular-type bearing member that takes the raw air into the case as a result of the rotation of the screw.
 5. The compressor according to claim 3, wherein the driving motor is provided at a face section on a first side of the case section; and the raw air intake section of the output shaft is provided at a face section on a second side of the case section, the second side being on the opposite side to the first side.
 6. The compressor according to claim 4, wherein the driving motor is provided at a face section on a first side of the case section; and the raw air intake section of the output shaft is provided at a face section on a second side of the case section, the second side being on the opposite side to the first side.
 7. The compressor according to claim 5, wherein a hood member for covering the raw air intake section of the output shaft is provided at the case section.
 8. The compressor according to claim 6, wherein a hood member for covering the raw air intake section of the output shaft is provided at the case section.
 9. An oxygen concentrator comprising a compressor that generates compressed air by compression of raw air, and an adsorption member that holds an adsorbent that adsorbs nitrogen from the compressed air, wherein the compressor has a case section and a driving motor that is provided in the case section and that has an output shaft; a head section operated by the rotation of the output shaft of the driving motor and that sucks and compresses the raw air to generate thereby the compressed air; a raw air intake section that is provided at the output shaft and that takes the raw air to be supplied to the head section, as a result of the rotation of the output shaft; and a pressure regulation section that regulates the pressure within the case section upon suction of the raw air and upon discharge of the generated compressed air. 